Trimming mechanism for sewing machines



J. R. MOFFATT.

TRIMIVIING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED APR.26, 1915.

1,312,41 3. I Patented Aug. 5,1919.

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1. R. MbFFATT. TRIMMING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED APR-26 1915- 1,312,413, Patented Aug. 5,1919.

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J. R. MOFFATT. I TRIMMING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED APR-26. 1915- 1.,3 1 2,4 1 3 Patented Aug. 5, 1919.

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JAMES R. MOF'FATT, OF CHICAGO,

UNION SPECIAL MACHINE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION or rLnrNoIs.

TRIMMING MECHANISM FOR SEWING-MACHINES.

Specification of Letters Patent.

Patented Aug. 5, 1919.

Application filed A ruae, 1915. Serial No. 23,390, i

To all whom it may concern:

Beit known that I, JAMES R. MorFATT, a citizen of the United States, residing at hicago, in the county of Cook, State of of Illinois, have invented certain new and useful Improvements in Trimming Mechanism for Sewing-Machines, of which the following is a description, reference being had to the accompanying drawing and to the figures of reference marked thereon.

e invention relates to new anduseful improvements in trimming mechanisms for sewing machines and more particularly to a trimming mechanism wherein the fabric is cut by a movable trimming member mounted beneath the work support.

An object of the invention is to provide a trimming mechanism wherein the movable trimming member projects rearwardly from its supporting means to a point adj acent the stitching mechanism, so that the fabric may be trimmed in advance of the stitching may be cut and the fabric stitched.

A further object of the invention is to provide a trimming mechanism of the above character with a positive train of mech anism for oscillating the movable arm carrying the trimming blade from the feed rocker of the sewing machine. 7

A still further object of the invention is to provide atrimming mechanism of the above character with means for supporting the fixed trimming blade on the presser foot so that said fixed blade may be readily adjusted'l aterally for varying the trimming position relative to the stitch forming mechanism. v

These and other objects will in part be obvious and will in part be hereinafter more fully describe v In the drawings, which show illustration, tiona Figure 1 is an end view ofa sewing ma chine having my improved trimming mech anism applied thereto, parts being broken away to show the under trimmer;

by way of one embodiment of the inven- Fig. 2 is a transverse sectional view through the sewing machine with the work support removed and showing the train of mechanism for actuating the trimmer blade inside elevation; v

Fig.3 is a plan view of the same;

Fig. 4 is a detail view partly in perspect1ve and partly in section showing the supporting arm for the lower trimming member, the bracket on which said arm is mounted and also the upper trimming member andvthe means for carrying the same;

Fig. 5 is an enlarged detail View, partly in section, showing the relative position of the movable trimmer, the fixed trimmer and the edge guide for guiding the fabric to which the trimmed strip is to be stitched;

F 1g. 6 is a sectional view through the presse-r foot, looking toward the front end of the foot, also showing the lower trimmmg member and the means for supporting the same, a

Fig. 7 is adetail showing themanner of adjustably'supporting the upper trimming member-on the'presser foot; I

Fig. 8 is a diagrammatic view. showing two sections of fabric trimmed and stitched on" myimproved machine; a i

igl 9 is a perspective view of, the sup- Iiorating bracket for the upper trimming a e. a I.

a I have shown my improved trimming mechanism applied to a sewing machine which consists of 'a supporting bed 1, carrying awork support 2 and an overhanging arm 3, in which reciprocates a needle bar l carrying a needle 5. Thisneedle bar I is'mounted to reciprocate in a needle gate 6 which is vibrated laterally so 'as'to produce a line of zig 'zag stitches. Also mounted in the overhanging arm is a presserbar 7 carrying a presser foot 8. These parts are of the usual construction and further description thereof is not thought necessary. My improved trimming mechanism consists of an upper fixedblade 9 which is mounted on a presse'rfoot Sand a lower movable bla e 10. *The presser foot is provided with the usual needleslot 11 V Said presser foot extends forward of the needle slot and carries a bracket 12' which is adjustablyattached to thepresser footby a screw 13 passing through a "slot in a shank fixed to I split and is formed with 'a dovetailed groove in' which the trimming blade 9 is located and a set screw 15 passing through the split sections of the bracket clamps the blade in ad usted positions. Said bracket is provided with a-plate 16 which is secured thereto by a screw 17 and this plate forms a conjustably I '32.. This arm 32 is split anda screw 33 pass- In Fig. 8 I have shown an upper section of fabric S which is adapted to be stitched to a lower section of fabric L and the lower section of fabric is trimmed at L. The upper section of fabric S is fed through the space 18 above described and the said fabric is guided by an edge guide and directing plate 19. Said plate is adjustably attached to the presser foot by a screw 20 which passes through a slot 21 in the shank of this edge guide. Said guide 19 has a shoulder 22 against which the edge of the fabric is guided. As clearly shown in Fig. 3 this edge guide is so located that the edge of the fabric will pass between the extreme throws of the needle. In Fig. 8 of the drawings 1 have shown at N one throw of the needle and at N the other throw thereof which lays the needle thread in a zig zag line over the edgeof the fabric strip S. Cooperating with the needle beneath the work support is a looper 23 which lays a thread N joining the loops in the threads N and N. V

The trimming blade 9 extends to a point so that its lower inclined edge is substantially flush with and parallel to the lower ftce of the extension of the presser foot. This trimming blade 9 projects forwardly away from the needle so that as it is ground to maintain asharp cutting edge the life of the trimming blade, over the ordinary blade, will be extended. 7

Said presser foot 8 is provided with a yielding section 24 located so as to bear on the strip S. Cooperating with this presser foot is a feed dog 25 carried by a feed bar 26 which is pivoted at its rear end to a feed rocker 27. This feed rocker is pivoted at 28 to the bed plate 1 of the machine. The feed rocker is oscillated by an arm 29 which is connected by means of a link toan adjustable crank pin on the end of the main shaft 30. The feed bar 26 is raised and lowered by. an" eccentric 31 on the main shaft 30. This feeding mechanism is of the usual construction and further. description thereof is not thought necessary.

The movable trimming blade 10 is ad fixed to the outer end of an arm ing through the split sections is adapted to clamp the blade in adjusted positions in the arm. Said'blade is dove tailed in cross section and fits within a dovetailed recess in the arm. The arm 32 has anopening therethrough in which is a supporting rod 34 This rod 34'is. mounted in a .braoket 35 and the bracket 35 is adjustably secured to the bed plate 1 by screws 36 and 37. Also mounted on the rod 34 is an arm 38. This arm 38 depends from the rod 34 and also extends horizontally to one side of the rod at its upper end as clearly shown in Fig. 4. The arm 32 carrying the trimming blade also extends to one side of the rod 34 and is provided with a lateral extension 39 which is clamped to the lateral extension 40 of the arm 38 by means of screws 41. These screws pass through slots in the extension 39 and thus permit the arm 32 to be adjusted lengthwise of the supportiing rod 34. The extension 40 of the arm 38 carries a collar 42 which engages the rod'34. Between the collar 42 and the arm 38 is a projecting portion 43 of the bracket 35. This projecting portion of the bracket holds the arm 38 from endwise movement on the rod. By loosening the screws 41 the arm 32 carrying the lower trimming blade may however, be readily adjusted to a limited extent in the direction endwise of the rod 34. As above noted the upper trimming blade is mounted on the presser foot so that the same may be adjusted laterally and this lower trimming blade may also be laterally adjusted and thus the trimming mechanism may be positioned properly for trimming an edge which is to be subsequently covered by. the stitching mechanism. The entire bracket 35 may be adjusted by loosening the screws 36 and 37, which permits further adjustment of the trimming mechanism;

The arm 38 is connected to a link 44 which is in turn pivoted to a lever 45 at 46. The lever 45 is fulcrumed at 47 on a bracket 48 and extends above said fulcrum where it is pivoted at 49 to a link 50, which .is in turn pivoted at 51 to the feed rocker 27. As the feed rocker moves back and forth the link 50 oscillates the lever 45 which in turn, through the link 44, oscillates the arm 38 and this raises and lowers the arm 32 carrying the movable trimming blade. By adjusting the length of the link 50 or the link 44, the vibrating'position of the arm 32 may be readily shifted to vary the limit of the upward stroke of the movable trimming blade when it is desired to trim thicker or thinner fabrics as the case may be. As clearlyshown in Fig. 5 of the drawings, the cutting edge of the movable blade 10 is inclined upwardly and from front to rear, so that onthe first part of the cutting movement ofthe blade, the real part of the blade will first cut the fabric, so that a proper shearing action is secured.

From the-above description, it will be apparent that I have provided a trimming mechanism wherein the lower trimming mechanism is carried by an. arm projecting rearwardly from its supporting frame to a The point of trimming the material may be very close to the needle and looper, in view of this manner of supporting of the trimming member, and, therefore, the material being stitchedmay be turned about very sharp curves and trimmed in advance of the stitching. Therefore, one of the particular advantages of the structure herein disclosed is this trimming at a point close to the stitching mechanism and in advance thereof.

It is obvious that minor changes in the details of construction and arrangement of parts may be made without departing from the spirit of the invention, as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Let ters Patent, is a 1. A trimming mechanism for sewing machines including in combination, a work support, a presser foot having a needle slot, a trimming blade carried by the presser foot and having its cutting edge substantially flush with the lower face of said presser foot and in advance of said needle slot, a movable trimming blade mounted beneath the work support and adapted to be moved upwardly against the cutting blade carried by the presser foot for cutting the fabric, a swinging arm carrying the movable blade, a bracket on which said swinging arm is mounted, and means for positively oscillating said swinging arm, said presser foot being cut away in rear of the trimming blade carried thereby in order to permit a fabric to be guided to the stitch forming mechanism in rear of the trimming blade.

2. A trimming mechanism for sewing machines including in combination a work support, a movable trimming blade beneath the work support, a swinging arm on which said movable blade is mounted, a bracket, a rod carried by said bracket on which said arm is mounted, a second arm on said rod and held from endwise movement thereon, an extension carried by said second arm, an extension carried by the first named arm and having an adjustable connection with the extension on the second arm whereby said first named arm may be adjusted lengthwise of said rod and means for positively oscillating said second named arm.

3. A trimming mechanism for sewing machines including in combination a work support, a presser foot, a trimming blade carried by said presser foot and having its cutting edge substantially flush with the lower face of said presser foot, a feeding mechanism including a feed rocker, a movable trimming blade beneath the work support and adapted to be moved upwardly against the cutting blade carried by the presser foot for cutting the fabric, a swinging arm carrying said movable blade, a bracket on which said swinging arm is mounted and means for positively oscillating said swinging arm from said feed rocker.

4. A trimming mechanism for sewing machines including in combination a work support, a presser foot, a trimming blade carried by said presser foot and having its cutting edge substantially flush with the lower face of said presser foot, a feeding mechanism including a feed rocker, a movable blade beneath the work support and movable upwardly against the blade carried by the presser foot for cutting the fabric, a swinging arm carrying said movable blade, a supporting bracket for said swinging arm, a second arm mounted on said bracket and connected to said first named arm and means for positively oscillating said second arm from said feed rocker. t

5. A trimming mechanism for sewing machines including in combination a work support, a presser foot, a trimming blade carried by said presser foot and having its cutting edge substantially flush with the lower face of said presser foot, a feeding mecha nism including a feed rocker, a movable blade beneath the work support and movable upwardly against the blade carried by the presser foot for cutting the fabric, a swinging arm carrying said movable blade, a sup porting bracket for said swinging arm, a second arm mounted on said bracket and connected to said first named arm and means for positively oscillating said second named arm from said feed rocker, said last named means including a lever, a bracket supporting said lever, a link connecting one end of the lever to the feed rocker and a link connecting the other end of the lever to said second arm.

6. A trimming mechanism for sewing machines including in combination a work sup port, a presser foot having a needle slot therein, a bracket carried by the presser foot and adjustable laterally thereof, a fixed trimming blade adjustably carried by said bracket, a movable trimming blade beneath the work support and cooperating with said fixed blade on the presser foot and means whereby said movable blade may be positively oscillated.

7. A trimming mechanism for sewing machines, including in combination a work sup-- port, a presser foot having a needle slot therein, a bracket carried by the presser foot in advance of the needle slot and adjustable laterally of said presser foot, a fixed trimming blade carried by said bracket, a movable trimming blade beneath the work support and cooperating with said fixed blade on the presser foot and means whereby said movable blade may be positively oscillated, and means whereby said movable blade may be adjusted laterally to correspond to the adjustment of said fixed blade.

8. A trimming mechanism for sewing machines, including in combination a work sup port, stitch forming mechanism, a Presser foot, a removably fixed trimming blade carried by the presser foot in advance of the stitch forming mechanism, said presser foot being cut away to permit a fabric to be guided to the stitch forming mechanism in rear of the trimming blade, the lower movable trimming blade adapted to cooperate with the fixed blade on the presser foot for trimming the fabric passing beneath the front portion of said presser foot.

9. The combination of a work support, feeding mechanism stitching mechanism in- 15 eluding a looper operating in a plane at right angles to the direction of feed, and a trimming mechanism including a movable trimming blade disposed in advance of the stitching mechanism beneath the work support and operating in a vertical plane containing the line of feed, and said movable trimming blade having a penetrating point at the rear end of said blade and located in advance of the looper body.

In testimony whereof, I afliX my signature, in the presence of two witnesses.

JAMES R. MOFFATT. Witnesses:

S. GEORGE TATE, J OHN XV. MCLAIN.

Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of .Eaten'cs,

1 Washington, D. 0. Q 

